Objective To investigate the heterotopic odontogenesis ability ofDelta1 gene transfected human dental pulp stem cell (DPSC) and nanohydroxyapatite/collagen (nHAC) composite scaffold. Methods The cultured human DPSC was transfected with Delta1-enhanced green fluorescent protein recombinant retrovirus supernatant，and was selected by puromycin to obtain the positive cell clone. The experimental group contained the Delta1 transfected DPSC; however, the control group did not contain the Delta1 transfected DPSC but contained DPSC transfected with vectors only. The cells were seeded into the nHAC carriers and were cultured in the odonto-inductive medium. The growth of the transduced cells in the carriers was observed by the fluorescent phase contrast microscope and the scanning electron microscope (SEM). The cell-carrier composites were subcutaneously transplanted into the Delta1 transfected 8 nude mice (female, 8 weeks old). Eight weeks after operation,the composites were taken out and tested with the histological and the immunohistological methods.Results Green fluorescence was observed inthe cells in the experimental group, which were grown in the carriers by the fluorescent phase contrast microscope. Observed by SEM, great amounts of transduced DPSC were observed along the scaffold materials, even filling the porous structures of nHAC and secreting a lot of extracellular matrix. However, in the control group, much fewer cells were found in the carriers. All the 4 Delta1 transduced DPSC-nHAC composites produced dentin-like structures that lined the surfaces of some nHAC porous structures. The odontoblast-like cells extended the cytoplasmic processes into the dentinal matrix, which was interfaced with a pulp-like interstitial tissue infiltrated with the blood vessels. Dentin sialophosphoprotein was expressed in the odontoblast-like cells when immunohisochemistry was performed. The morphology of the control composite was a typical one of the fibrous connective tissue,and only a little dentin-like structure was found in 2 of the 8 control transplants. Conclution DPSC can be used as the recipient cell of the Delta1 gene for expression and secretion of the Delta1 protein. The composites of the transfected cells and nHAC can induce heterotopic odontogenesis, which indicates that Delta1 is a novel candidate for the gene enhanced dentinpulp composite engineering.
Objective To investigate the structure characteristics， functions， and research progress of Notch signaling pathway in digestive tumors. Methods The related literatures about the molecular genetic mechanism of Notch signaling pathway were reviewed. Results The Notch signaling pathway plays an important role not only in normal cells’ growth， differentiation， proliferation， and apoptosis but also in a variety of tumors’ occurrence and development. Conclusion The reasonable regulation to Notch signaling pathway may open up new ways to the treatment of the tumor.
Objective To investigate the role of Notch signaling pathway in pancreas development and pancreatic cancer. Methods The related literatures were reviewed and analyzed. Results Notch signaling played a role early in development by maintaining pancreatic epithelial cells in a progenitor state and delaying their differentiation until timely appropriate. Notch signaling was reactivated in the initiation and progression of pancreatic cancer. Conclusion Notch signaling pathway plays an important role in the pancreas development. Sustained Notch signaling activity promotes the progression of pancreatic cancer, and may be one of major factors in the initiation of pancreatic cancer.
ObjectiveTo detect the expression of Notch1, Bax, Bcl-2 genes in rat knee joint cartilage cells in a state of activation and inactivation of the Notch signaling pathway, and preliminarily study the mechanism of Notch signaling pathway on experimental rat knee osteoarthritis (OA) chondrocytes apoptosis.MethodsA total of 34 specefic-pathogen-free Sprague Dawley rats were selected, of which 32 were established the right knee OA models using Hulth method, and the other 2 were normally fed. Four weeks later, two randomly selected OA rats and the two normally fed rats were put to death, to observe the morphological changes of the right knee and ensure the OA models were successfully established by pathology examination. The remaining 30 rats were randomly divided into three groups with 10 in each. The rats were injected intra-articularly on each Tuesday and Friday, with Nocth signal pathway specific activator Jagged1 protein (25 ng/kg) in the activation group, γ-secretase inhibitor DAPT (GSI-IX) (100 ng/kg) in the inhibition group, and phosphate-buffered saline in the control group, respectively. The rats were sacrificed after 8 weeks of articular cavity injection. Taking the right knee articular cartilage speciments of femoral condyle, we observed the degeneration of articular cartilage of the three groups, observed the histomorphological changes by microscope, evaluated the Mankin scores, and used the immunohistochemistry to detect the expression of Notch1, Bax, Bcl-2 proteins.ResultsAfter the 8-week articular cavity injection, the Mankin scores in the activation group, the inhibition group, and the control group were 3.40±0.84, 6.70±0.95, 11.10±1.37, respectively, and the differences between the three groups were statistically significant (P<0.05). The positive rates of Notch1 and Bax of chondrocyte in the inhibition group were lower than those in the control group and the activation group (P<0.05), while the positive rate of Bcl-2 of chondrocyte in the inhibition group was higher than that in the control group and the activation group (P<0.05).ConclusionActivating the Notch signaling pathway may facilitate the chondrocyte apoptosis and aggravate OA by up-regulating Bax protein expression and down-regulating Bcl-2 protein expression; inhibiting the Notch signaling pathway may inhibit the chondrocyte apoptosis and relieve OA by up-regulating Bcl-2 protein expression and down-regulating Bax protein expression.
Objective To explore the effect of natural hirudin on proliferation of human microvascular endothelial cells (HMVECs) and its preliminary mechanism of promoting angiogenesis. Methods Three-dimensional culture models of HMVECs were established in vitro and observed by inverted phase contrast microscopy after 24 hours of culturing. Then, the three-dimensional culture models of HMVECs were treated with different concentrations (1, 4, and 7 ATU/mL) of the natural hirudin, respectively, and Dulbecco’s modified Eagle’s medium containing 10% fetal bovine serum as control. The cell proliferations of 4 groups were detected by cell counting kit 8 (CCK-8) method at 24, 48, and 72 hours; the angiogenesis of 4 groups were observed by tube formation assay at 24 hours; the expressions of vascular endothelial growth factor (VEGF) and Notch1 of HMVECs in 4 groups were observed by immunofluorescence staining at 24 hours. Results The observation of cells in three-dimensional culture models showed that HMVECs attached to Matrigel well, and the cells formed tube structure completely after 24 hours. The results of CCK-8 test showed that the absorbance (A) value of 1 and 4 ATU/mL groups were higher than that of control group at each time point (P<0.05), andA value of 4 ATU/mL group was the highest. The A value of 7 ATU/mL group was significantly lower than those of 1 and 4 ATU/mL groups and control group (P<0.05). The tube formation assay showed that the tube structure was more in 1 and 4 ATU/mL groups than in 7 ATU/mL group and control group, and in 4 ATU/mL group than in 1 ATU/mL group, showing significant differences (P<0.05). There was no significant difference between 7 ATU/mL group and control group (P>0.05). The results of immunofluorescence staining showed that compared with control group, the Notch1 expression was higher in 1 and 4 ATU/mL groups and lower in 7 ATU/mL group; and there was significant difference between 4 and 7 ATU/mL groups and control group (P<0.05). The VEGF expression was higher in 1, 4, and 7 ATU/mL groups than in control group, in 4 ATU/mL group than in 1 and 7 ATU/mL groups, showing significant differences (P<0.05). Conclusion Natural hirudin can promote angiogenesis at low and medium concentrations, but suppress angiogenesis at high concentrations. Its mechanism may be related to the VEGF-Notch signal pathway.
Objective To investigate the mechanism of bone morphogenetic protein-4 (BMP4) in promoting the recovery of small intestinal mucosal barrier function during the recovery period of small intestine ischemia-reperfusion (I/R) injury. Methods Twenty-eight C57BL/6J male mice aged 6–8 weeks were randomly selected and assigned to small intestine I/R group (n=24) and sham operation (SO) group (n=4) by random number table method. Small intestine I/R injury models of 24 mice were established, then 4 mice were randomly selected at 6, 12, 24 and 48 h after I/R established modeling and killed to observe the morphological changes of small intestinal mucosa and detect the expression of BMP4 mRNA in the jejunal epithelial cells, the other 8 mice were allocated for the experimental observation at the recovery period of small intestine I/R injury (24 h after I/R was selected as the observation time point of recovery period of small intestine I/R injury according to the pre-experimental results). Twelve mice were randomly divided into I/R-24 h-BMP4 group (recombinant human BMP4 protein was injected intraperitoneally), I/R-24 h-NS (normal saline) group (NS was injected intraperitoneally), and I/R-24 h-blank group (did nothing), 4 mice in each group. Then the small intestinal transmembrane electrical impedance (TER) was measured by Ussing chamber. The expressions of BMP4 protein and tight junction proteins (occludin and ZO-1), Notch signaling pathway proteins (Notch1 and Jagged1), and Smad6 protein were detected by Western blot. Results At 24 h after I/R injury, the injuries of villous epithelium, edema, and a small part of villi were alleviated. The BMP4 mRNA expressions at 6, 12, 24 and 48 h after I/R injury in the small intestinal epithelial cells were increased as compared with the SO group. Compared with the I/R-24 h-NS group and the I/R-24 h-blank group, the TER was increased, and the expression levels of occludin, ZO-1, p-Smad6, Notch1, Jagged1 were increased in the I/R-24 h-BMP4 group. Conclusion From the preliminary results of this study, during recovery period of small intestine I/R injury, the expression of BMP4 in small intestinal epithelial cells is increased, permeability of jejunal mucosal barrier is increased, which might promote the recovery of small intestinal mucosal barrier function by activating the Notch signaling pathway (Notch1 and Jagged1), Smad classic signaling pathway, and promoting the increase of tight junction protein expression (occludin and ZO-1).
Objective To observe the effects of fine particulate matter (PM2.5) on airway remodeling and Notch signaling pathway in mice with bronchial asthma, and explore the possible mechanism of its influence on airway remodeling in asthmatic mice. Methods Forty eight-week-old SPF female BALB/c mice were divided into a healthy control group, a healthy PM2.5 group, an asthma group and an asthma PM2.5 group by random number table, with 10 mice in each group. The asthma group and the asthma PM2.5 group were sensitized with ovalbumin to establish asthma mouse model, and the healthy PM2.5 group and the asthma PM2.5 group received aerosol inhalation of PM2.5 (510 μg/m3) after each provocation. After modeling, lung function was measured in each group. Hematoxylin and eosin staining and Masson staining were performed on the lung tissue sections of mice. Image analysis software was used to determine the circumference of the bronchial basement membrane, the total area of the bronchial wall, the area of bronchial smooth muscle and the area of collagen deposition. The expressions of Notch1, Hes1, α-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1) and type Ⅰ collagen (Col-Ⅰ) were detected by immunohistochemistry and western blotting. The content of hydroxyproline (HYP) in lung tissue was determined by alkaline water method. Results The total airway wall area, airway smooth muscle area and collagen deposition area in the asthma group [(365.81±46.10), (132.80±20.14), (221.82±25.20) μm2/μm] were significantly higher than those in the healthy control group [(187.70±14.80), (89.73±8.49), (123.91±16.88) μm2/μm] (P<0.01). The healthy PM2.5 group [(244.62±42.86), (116.40±20.40), (174.91±57.41) μm2/μm] and the asthma PM2.5 group [(447.70±76.14), (236.14±36.35), (294.89±75.96) μm2/μm] were higher than those in the control group (all P<0.01). The expressions of Notch1, Hes1, α-SMA, TGF-β1 and Col-Ⅰ were strongly positive in the lung tissues of the asthmatic mice, but weak in the healthy control group. After PM2.5 intervention, compared with the control group, the expression intensity of the above molecules increased. Notch1 receptor and downstream Hes1 protein in the asthma group (0.86±0.10, 1.02±0.06) were significantly higher than those in the healthy control group (0.26±0.07, 0.56±0.09) (all P<0.01). The healthy PM2.5 group (0.44±0.06, 0.77±0.07) and asthma PM2.5 group (1.33±0.23, 1.25±0.18) were higher than the control group (all P<0.01). Airway remodeling related molecules α-SMA, TGF-β1 and Col-Ⅰ protein in the asthma group (0.60±0.04, 0.52±0.09, 0.36±0.04) were significantly higher than those in the healthy control group (0.31±0.03, 0.22±0.04, 0.23±0.04) (all P<0.01). The health PM2.5 group (0.49±0.02, 0.30±0.03, 0.28±0.03) and the asthma PM2.5 group (0.88±0.09, 0.62±0.03, 0.49±0.07) were higher than the control group (P<0.05 or P<0.01), respectively. The content of HYP in lung tissue of the asthma group (57.71±7.60) μg/100mg was significantly higher than that of healthy control group (40.53±5.73) μg/100mg. The healthy PM2.5 group (53.92±6.82) μg/100mg and asthma PM2.5 group (70.96±4.44) μg/100mg were higher than the control group (P<0.01), respectively. In asthma group and asthma PM2.5 group, the expression of Notch1 and Hes1 protein was positively correlated with the total airway wall area, airway smooth muscle area, collagen deposition area, α-SMA, TGF-β1, Col-Ⅰ and HYP (all P<0.01). Conclusion PM2.5 can promote early airway remodeling in asthma, and the activation of Notch signaling pathway may be involved in the promoting effect of PM2.5 on early airway remodeling.